The original Cats were purely monophonic, but then came the SRM update which added the duophonic (2-voice) capability. The Cat (SRM) has a 2-note sample-and-hold feature for each voice too! The Keyboard can be switched between 2-voice (poly) and 1-voice (mono) modes. In mono mode the 2 oscillators can be stacked for a rich mono-bass or mono-lead synth sound. Poly mode limits the richness of the sound because each VCO becomes a separate dedicated voice. In this mode you can create slightly more complex melodies with overlapping notes or very basic pads. The sub-osc plays at an octave below the actual note played which nicely adds some warmth or bottom to your sounds. It has been used by The Dust Brothers, Chemical Brothers, Devo, Rod Argent, David Bedford, Lyn Berger, Dave Greenslade, OMD, Loaded and Mixmaster Morris.